<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      console.log(typeof 100); // number
      console.log(typeof "hello"); // string
      console.log(typeof true); // boolean
      console.log(typeof undefined); // undefined
      console.log(typeof {}); // object
      console.log(typeof Symbol()); // symbol
      console.log(typeof null); // object ×  null √
    </script>
  </body>
</html>
